cpu-o3,tests: add page boundary access test

The O3 model supports unaligned accesses across page boundaries.
This changeset provides a stress test for the feature.

Other benchmarks exercise it, but their coverage is spotty. This
test does nothing else except poke bytes which straddle page
boundaries.

Change-Id: Ic20c2862bcb7af7be091030c12916ba499db10c7
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22303
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

tests/test-progs/page-access-wrap/Makefile

@@ -0,0 +1,20 @@
+
+CPP := g++
+
+TEST_OBJS := page-access-wrap.o
+TEST_PROGS := $(TEST_OBJS:.o=)
+
+# ==== Rules ==================================================================
+
+.PHONY: default clean
+
+default: $(TEST_PROGS)
+
+clean:
+	$(RM)  $(TEST_OBJS) $(TEST_PROGS)
+
+$(TEST_PROGS): $(TEST_OBJS)
+	$(CPP)  -static -o $@  $@.o
+
+%.o: %.c Makefile
+	$(CPP) -c -o $@ $*.c -msse3

tests/test-progs/page-access-wrap/page-access-wrap.cpp

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2019 Advanced Micro Devices, Inc.
+ * All rights reserved.
+ *
+ * For use for simulation and test purposes only
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ * contributors may be used to endorse or promote products derived from this
+ * software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Brandon Potter
+ */
+
+#include <sys/mman.h>
+
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <ctime>
+
+int main(void)
+{
+    uint64_t page_size = 0x1000;
+    uint64_t num_pages = 0x10000;
+    uint64_t length = page_size * num_pages;
+
+    void *raw = mmap(NULL, length, PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
+    uint8_t *mem = reinterpret_cast<uint8_t*>(raw);
+
+    srand(0xABCD);
+
+    uint64_t last_byte = page_size - 1;
+    uint64_t page_boundaries = num_pages - 1;
+
+    for (int i = 0; i < 2000; i++) {
+        uint64_t random_boundary = rand() % page_boundaries;
+        uint64_t boundary_offset = random_boundary * page_size;
+        uint64_t boundary_last_byte = boundary_offset + last_byte;
+        uint32_t *poke = reinterpret_cast<uint32_t*>(mem + boundary_last_byte);
+        printf("%p\n", poke);
+        uint32_t value = *poke;
+    }
+
+    return 0;
+}